/* deflate.c -- compress data using the deflation algorithm
 * Copyright (C) 1995-2012 Jean-loup Gailly and Mark Adler
 * For conditions of distribution and use, see copyright notice in zlib.h
 */

/*
 *  ALGORITHM
 *
 *      The "deflation" process depends on being able to identify portions
 *      of the input text which are identical to earlier input (within a
 *      sliding window trailing behind the input currently being processed).
 *
 *      The most straightforward technique turns out to be the fastest for
 *      most input files: try all possible matches and select the longest.
 *      The key feature of this algorithm is that insertions into the string
 *      dictionary are very simple and thus fast, and deletions are avoided
 *      completely. Insertions are performed at each input character, whereas
 *      string matches are performed only when the previous match ends. So it
 *      is preferable to spend more time in matches to allow very fast string
 *      insertions and avoid deletions. The matching algorithm for small
 *      strings is inspired from that of Rabin & Karp. A brute force approach
 *      is used to find longer strings when a small match has been found.
 *      A similar algorithm is used in comic (by Jan-Mark Wams) and freeze
 *      (by Leonid Broukhis).
 *         A previous version of this file used a more sophisticated algorithm
 *      (by Fiala and Greene) which is guaranteed to run in linear amortized
 *      time, but has a larger average cost, uses more memory and is patented.
 *      However the F&G algorithm may be faster for some highly redundant
 *      files if the parameter max_chain_length (described below) is too large.
 *
 *  ACKNOWLEDGEMENTS
 *
 *      The idea of lazy evaluation of matches is due to Jan-Mark Wams, and
 *      I found it in 'freeze' written by Leonid Broukhis.
 *      Thanks to many people for bug reports and testing.
 *
 *  REFERENCES
 *
 *      Deutsch, L.P.,"DEFLATE Compressed Data Format Specification".
 *      Available in http://tools.ietf.org/html/rfc1951
 *
 *      A description of the Rabin and Karp algorithm is given in the book
 *         "Algorithms" by R. Sedgewick, Addison-Wesley, p252.
 *
 *      Fiala,E.R., and Greene,D.H.
 *         Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595
 *
 */

/* @(#) $Id$ */

#include "deflate.h"

const char deflate_copyright[] =
	" deflate 1.2.7 Copyright 1995-2012 Jean-loup Gailly and Mark Adler ";
/*
  If you use the zlib library in a product, an acknowledgment is welcome
  in the documentation of your product. If for some reason you cannot
  include such an acknowledgment, I would appreciate that you keep this
  copyright string in the executable of your product.
 */

/* ===========================================================================
 *  Function prototypes.
 */
typedef enum
{
	need_more,      /* block not completed, need more input or more output */
	block_done,     /* block flush performed */
	finish_started, /* finish started, need only more output at next deflate */
	finish_done     /* finish done, accept no more input or output */
} block_state;

typedef block_state( *compress_func ) OF( ( deflate_state* s, int flush ) );
/* Compression function. Returns the block state after the call. */

local void fill_window    OF( ( deflate_state* s ) );
local block_state deflate_stored OF( ( deflate_state* s, int flush ) );
local block_state deflate_fast   OF( ( deflate_state* s, int flush ) );
#ifndef FASTEST
	local block_state deflate_slow   OF( ( deflate_state* s, int flush ) );
#endif
local block_state deflate_rle    OF( ( deflate_state* s, int flush ) );
local block_state deflate_huff   OF( ( deflate_state* s, int flush ) );
local void lm_init        OF( ( deflate_state* s ) );
local void putShortMSB    OF( ( deflate_state* s, uInt b ) );
local void flush_pending  OF( ( z_streamp strm ) );
local int read_buf        OF( ( z_streamp strm, Bytef* buf, unsigned size ) );
#ifdef ASMV
	void match_init OF( ( void ) ); /* asm code initialization */
	uInt longest_match  OF( ( deflate_state* s, IPos cur_match ) );
#else
	local uInt longest_match  OF( ( deflate_state* s, IPos cur_match ) );
#endif

#ifdef DEBUG
local  void check_match OF( ( deflate_state* s, IPos start, IPos match,
							  int length ) );
#endif

/* ===========================================================================
 * Local data
 */

#define NIL 0
/* Tail of hash chains */

#ifndef TOO_FAR
	#define TOO_FAR 4096
#endif
/* Matches of length 3 are discarded if their distance exceeds TOO_FAR */

/* Values for max_lazy_match, good_match and max_chain_length, depending on
 * the desired pack level (0..9). The values given below have been tuned to
 * exclude worst case performance for pathological files. Better values may be
 * found for specific files.
 */
typedef struct config_s
{
	ush good_length; /* reduce lazy search above this match length */
	ush max_lazy;    /* do not perform lazy search above this match length */
	ush nice_length; /* quit search above this match length */
	ush max_chain;
	compress_func func;
} config;

#ifdef FASTEST
local const config configuration_table[2] =
{
	/*      good lazy nice chain */
	/* 0 */ {0,    0,  0,    0, deflate_stored},  /* store only */
	/* 1 */ {4,    4,  8,    4, deflate_fast}
}; /* max speed, no lazy matches */
#else
local const config configuration_table[10] =
{
	/*      good lazy nice chain */
	/* 0 */ {0,    0,  0,    0, deflate_stored},  /* store only */
	/* 1 */ {4,    4,  8,    4, deflate_fast}, /* max speed, no lazy matches */
	/* 2 */ {4,    5, 16,    8, deflate_fast},
	/* 3 */ {4,    6, 32,   32, deflate_fast},

	/* 4 */ {4,    4, 16,   16, deflate_slow},  /* lazy matches */
	/* 5 */ {8,   16, 32,   32, deflate_slow},
	/* 6 */ {8,   16, 128, 128, deflate_slow},
	/* 7 */ {8,   32, 128, 256, deflate_slow},
	/* 8 */ {32, 128, 258, 1024, deflate_slow},
	/* 9 */ {32, 258, 258, 4096, deflate_slow}
}; /* max compression */
#endif

/* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4
 * For deflate_fast() (levels <= 3) good is ignored and lazy has a different
 * meaning.
 */

#define EQUAL 0
/* result of memcmp for equal strings */

#ifndef NO_DUMMY_DECL
struct static_tree_desc_s
{
	int dummy;
}; /* for buggy compilers */
#endif

/* rank Z_BLOCK between Z_NO_FLUSH and Z_PARTIAL_FLUSH */
#define RANK(f) (((f) << 1) - ((f) > 4 ? 9 : 0))

/* ===========================================================================
 * Update a hash value with the given input byte
 * IN  assertion: all calls to to UPDATE_HASH are made with consecutive
 *    input characters, so that a running hash key can be computed from the
 *    previous key instead of complete recalculation each time.
 */
#define UPDATE_HASH(s,h,c) (h = (((h)<<s->hash_shift) ^ (c)) & s->hash_mask)


/* ===========================================================================
 * Insert string str in the dictionary and set match_head to the previous head
 * of the hash chain (the most recent string with same hash key). Return
 * the previous length of the hash chain.
 * If this file is compiled with -DFASTEST, the compression level is forced
 * to 1, and no hash chains are maintained.
 * IN  assertion: all calls to to INSERT_STRING are made with consecutive
 *    input characters and the first MIN_MATCH bytes of str are valid
 *    (except for the last MIN_MATCH-1 bytes of the input file).
 */
#ifdef FASTEST
#define INSERT_STRING(s, str, match_head) \
   (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \
    match_head = s->head[s->ins_h], \
    s->head[s->ins_h] = (Pos)(str))
#else
#define INSERT_STRING(s, str, match_head) \
   (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \
    match_head = s->prev[(str) & s->w_mask] = s->head[s->ins_h], \
    s->head[s->ins_h] = (Pos)(str))
#endif

/* ===========================================================================
 * Initialize the hash table (avoiding 64K overflow for 16 bit systems).
 * prev[] will be initialized on the fly.
 */
#define CLEAR_HASH(s) \
    s->head[s->hash_size-1] = NIL; \
    zmemzero((Bytef *)s->head, (unsigned)(s->hash_size-1)*sizeof(*s->head));

/* ========================================================================= */
int ZEXPORT deflateInit_( strm, level, version, stream_size )
z_streamp strm;
int level;
const char* version;
int stream_size;
{
	return deflateInit2_( strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL,
						  Z_DEFAULT_STRATEGY, version, stream_size );
	/* To do: ignore strm->next_in if we use it as window */
}

/* ========================================================================= */
int ZEXPORT deflateInit2_( strm, level, method, windowBits, memLevel, strategy,
						   version, stream_size )
z_streamp strm;
int  level;
int  method;
int  windowBits;
int  memLevel;
int  strategy;
const char* version;
int stream_size;
{
	deflate_state* s;
	int wrap = 1;
	static const char my_version[] = ZLIB_VERSION;

	ushf* overlay;
	/* We overlay pending_buf and d_buf+l_buf. This works since the average
	 * output size for (length,distance) codes is <= 24 bits.
	 */

	if( version == Z_NULL || version[0] != my_version[0] ||
			stream_size != sizeof( z_stream ) )
	{
		return Z_VERSION_ERROR;
	}
	if( strm == Z_NULL )
	{
		return Z_STREAM_ERROR;
	}

	strm->msg = Z_NULL;
	if( strm->zalloc == ( alloc_func )0 )
	{
#ifdef Z_SOLO
		return Z_STREAM_ERROR;
#else
		strm->zalloc = zcalloc;
		strm->opaque = ( voidpf )0;
#endif
	}
	if( strm->zfree == ( free_func )0 )
#ifdef Z_SOLO
		return Z_STREAM_ERROR;
#else
		strm->zfree = zcfree;
#endif

#ifdef FASTEST
	if( level != 0 )
	{
		level = 1;
	}
#else
	if( level == Z_DEFAULT_COMPRESSION )
	{
		level = 6;
	}
#endif

	if( windowBits < 0 )  /* suppress zlib wrapper */
	{
		wrap = 0;
		windowBits = -windowBits;
	}
#ifdef GZIP
	else if( windowBits > 15 )
	{
		wrap = 2;       /* write gzip wrapper instead */
		windowBits -= 16;
	}
#endif
	if( memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != Z_DEFLATED ||
			windowBits < 8 || windowBits > 15 || level < 0 || level > 9 ||
			strategy < 0 || strategy > Z_FIXED )
	{
		return Z_STREAM_ERROR;
	}
	if( windowBits == 8 )
	{
		windowBits = 9;    /* until 256-byte window bug fixed */
	}
	s = ( deflate_state* ) ZALLOC( strm, 1, sizeof( deflate_state ) );
	if( s == Z_NULL )
	{
		return Z_MEM_ERROR;
	}
	strm->state = ( struct internal_state FAR* )s;
	s->strm = strm;

	s->wrap = wrap;
	s->gzhead = Z_NULL;
	s->w_bits = windowBits;
	s->w_size = 1 << s->w_bits;
	s->w_mask = s->w_size - 1;

	s->hash_bits = memLevel + 7;
	s->hash_size = 1 << s->hash_bits;
	s->hash_mask = s->hash_size - 1;
	s->hash_shift = ( ( s->hash_bits + MIN_MATCH - 1 ) / MIN_MATCH );

	s->window = ( Bytef* ) ZALLOC( strm, s->w_size, 2 * sizeof( Byte ) );
	s->prev   = ( Posf* )  ZALLOC( strm, s->w_size, sizeof( Pos ) );
	s->head   = ( Posf* )  ZALLOC( strm, s->hash_size, sizeof( Pos ) );

	s->high_water = 0;      /* nothing written to s->window yet */

	s->lit_bufsize = 1 << ( memLevel + 6 ); /* 16K elements by default */

	overlay = ( ushf* ) ZALLOC( strm, s->lit_bufsize, sizeof( ush ) + 2 );
	s->pending_buf = ( uchf* ) overlay;
	s->pending_buf_size = ( ulg )s->lit_bufsize * ( sizeof( ush ) + 2L );

	if( s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL ||
			s->pending_buf == Z_NULL )
	{
		s->status = FINISH_STATE;
		strm->msg = ( char* )ERR_MSG( Z_MEM_ERROR );
		deflateEnd( strm );
		return Z_MEM_ERROR;
	}
	s->d_buf = overlay + s->lit_bufsize / sizeof( ush );
	s->l_buf = s->pending_buf + ( 1 + sizeof( ush ) ) * s->lit_bufsize;

	s->level = level;
	s->strategy = strategy;
	s->method = ( Byte )method;

	return deflateReset( strm );
}

/* ========================================================================= */
int ZEXPORT deflateSetDictionary( strm, dictionary, dictLength )
z_streamp strm;
const Bytef* dictionary;
uInt  dictLength;
{
	deflate_state* s;
	uInt str, n;
	int wrap;
	unsigned avail;
	unsigned char* next;

	if( strm == Z_NULL || strm->state == Z_NULL || dictionary == Z_NULL )
	{
		return Z_STREAM_ERROR;
	}
	s = strm->state;
	wrap = s->wrap;
	if( wrap == 2 || ( wrap == 1 && s->status != INIT_STATE ) || s->lookahead )
	{
		return Z_STREAM_ERROR;
	}

	/* when using zlib wrappers, compute Adler-32 for provided dictionary */
	if( wrap == 1 )
	{
		strm->adler = adler32( strm->adler, dictionary, dictLength );
	}
	s->wrap = 0;                    /* avoid computing Adler-32 in read_buf */

	/* if dictionary would fill window, just replace the history */
	if( dictLength >= s->w_size )
	{
		if( wrap == 0 )             /* already empty otherwise */
		{
			CLEAR_HASH( s );
			s->strstart = 0;
			s->block_start = 0L;
			s->insert = 0;
		}
		dictionary += dictLength - s->w_size;  /* use the tail */
		dictLength = s->w_size;
	}

	/* insert dictionary into window and hash */
	avail = strm->avail_in;
	next = strm->next_in;
	strm->avail_in = dictLength;
	strm->next_in = ( Bytef* )dictionary;
	fill_window( s );
	while( s->lookahead >= MIN_MATCH )
	{
		str = s->strstart;
		n = s->lookahead - ( MIN_MATCH - 1 );
		do
		{
			UPDATE_HASH( s, s->ins_h, s->window[str + MIN_MATCH - 1] );
#ifndef FASTEST
			s->prev[str & s->w_mask] = s->head[s->ins_h];
#endif
			s->head[s->ins_h] = ( Pos )str;
			str++;
		}
		while( --n );
		s->strstart = str;
		s->lookahead = MIN_MATCH - 1;
		fill_window( s );
	}
	s->strstart += s->lookahead;
	s->block_start = ( long )s->strstart;
	s->insert = s->lookahead;
	s->lookahead = 0;
	s->match_length = s->prev_length = MIN_MATCH - 1;
	s->match_available = 0;
	strm->next_in = next;
	strm->avail_in = avail;
	s->wrap = wrap;
	return Z_OK;
}

/* ========================================================================= */
int ZEXPORT deflateResetKeep( strm )
z_streamp strm;
{
	deflate_state* s;

	if( strm == Z_NULL || strm->state == Z_NULL ||
			strm->zalloc == ( alloc_func )0 || strm->zfree == ( free_func )0 )
	{
		return Z_STREAM_ERROR;
	}

	strm->total_in = strm->total_out = 0;
	strm->msg = Z_NULL; /* use zfree if we ever allocate msg dynamically */
	strm->data_type = Z_UNKNOWN;

	s = ( deflate_state* )strm->state;
	s->pending = 0;
	s->pending_out = s->pending_buf;

	if( s->wrap < 0 )
	{
		s->wrap = -s->wrap; /* was made negative by deflate(..., Z_FINISH); */
	}
	s->status = s->wrap ? INIT_STATE : BUSY_STATE;
	strm->adler =
#ifdef GZIP
		s->wrap == 2 ? crc32( 0L, Z_NULL, 0 ) :
#endif
		adler32( 0L, Z_NULL, 0 );
	s->last_flush = Z_NO_FLUSH;

	_tr_init( s );

	return Z_OK;
}

/* ========================================================================= */
int ZEXPORT deflateReset( strm )
z_streamp strm;
{
	int ret;

	ret = deflateResetKeep( strm );
	if( ret == Z_OK )
	{
		lm_init( strm->state );
	}
	return ret;
}

/* ========================================================================= */
int ZEXPORT deflateSetHeader( strm, head )
z_streamp strm;
gz_headerp head;
{
	if( strm == Z_NULL || strm->state == Z_NULL )
	{
		return Z_STREAM_ERROR;
	}
	if( strm->state->wrap != 2 )
	{
		return Z_STREAM_ERROR;
	}
	strm->state->gzhead = head;
	return Z_OK;
}

/* ========================================================================= */
int ZEXPORT deflatePending( strm, pending, bits )
unsigned* pending;
int* bits;
z_streamp strm;
{
	if( strm == Z_NULL || strm->state == Z_NULL )
	{
		return Z_STREAM_ERROR;
	}
	if( pending != Z_NULL )
	{
		*pending = strm->state->pending;
	}
	if( bits != Z_NULL )
	{
		*bits = strm->state->bi_valid;
	}
	return Z_OK;
}

/* ========================================================================= */
int ZEXPORT deflatePrime( strm, bits, value )
z_streamp strm;
int bits;
int value;
{
	deflate_state* s;
	int put;

	if( strm == Z_NULL || strm->state == Z_NULL )
	{
		return Z_STREAM_ERROR;
	}
	s = strm->state;
	if( ( Bytef* )( s->d_buf ) < s->pending_out + ( ( Buf_size + 7 ) >> 3 ) )
	{
		return Z_BUF_ERROR;
	}
	do
	{
		put = Buf_size - s->bi_valid;
		if( put > bits )
		{
			put = bits;
		}
		s->bi_buf |= ( ush )( ( value & ( ( 1 << put ) - 1 ) ) << s->bi_valid );
		s->bi_valid += put;
		_tr_flush_bits( s );
		value >>= put;
		bits -= put;
	}
	while( bits );
	return Z_OK;
}

/* ========================================================================= */
int ZEXPORT deflateParams( strm, level, strategy )
z_streamp strm;
int level;
int strategy;
{
	deflate_state* s;
	compress_func func;
	int err = Z_OK;

	if( strm == Z_NULL || strm->state == Z_NULL )
	{
		return Z_STREAM_ERROR;
	}
	s = strm->state;

#ifdef FASTEST
	if( level != 0 )
	{
		level = 1;
	}
#else
	if( level == Z_DEFAULT_COMPRESSION )
	{
		level = 6;
	}
#endif
	if( level < 0 || level > 9 || strategy < 0 || strategy > Z_FIXED )
	{
		return Z_STREAM_ERROR;
	}
	func = configuration_table[s->level].func;

	if( ( strategy != s->strategy || func != configuration_table[level].func ) &&
			strm->total_in != 0 )
	{
		/* Flush the last buffer: */
		err = deflate( strm, Z_BLOCK );
	}
	if( s->level != level )
	{
		s->level = level;
		s->max_lazy_match   = configuration_table[level].max_lazy;
		s->good_match       = configuration_table[level].good_length;
		s->nice_match       = configuration_table[level].nice_length;
		s->max_chain_length = configuration_table[level].max_chain;
	}
	s->strategy = strategy;
	return err;
}

/* ========================================================================= */
int ZEXPORT deflateTune( strm, good_length, max_lazy, nice_length, max_chain )
z_streamp strm;
int good_length;
int max_lazy;
int nice_length;
int max_chain;
{
	deflate_state* s;

	if( strm == Z_NULL || strm->state == Z_NULL )
	{
		return Z_STREAM_ERROR;
	}
	s = strm->state;
	s->good_match = good_length;
	s->max_lazy_match = max_lazy;
	s->nice_match = nice_length;
	s->max_chain_length = max_chain;
	return Z_OK;
}

/* =========================================================================
 * For the default windowBits of 15 and memLevel of 8, this function returns
 * a close to exact, as well as small, upper bound on the compressed size.
 * They are coded as constants here for a reason--if the #define's are
 * changed, then this function needs to be changed as well.  The return
 * value for 15 and 8 only works for those exact settings.
 *
 * For any setting other than those defaults for windowBits and memLevel,
 * the value returned is a conservative worst case for the maximum expansion
 * resulting from using fixed blocks instead of stored blocks, which deflate
 * can emit on compressed data for some combinations of the parameters.
 *
 * This function could be more sophisticated to provide closer upper bounds for
 * every combination of windowBits and memLevel.  But even the conservative
 * upper bound of about 14% expansion does not seem onerous for output buffer
 * allocation.
 */
uLong ZEXPORT deflateBound( strm, sourceLen )
z_streamp strm;
uLong sourceLen;
{
	deflate_state* s;
	uLong complen, wraplen;
	Bytef* str;

	/* conservative upper bound for compressed data */
	complen = sourceLen +
			  ( ( sourceLen + 7 ) >> 3 ) + ( ( sourceLen + 63 ) >> 6 ) + 5;

	/* if can't get parameters, return conservative bound plus zlib wrapper */
	if( strm == Z_NULL || strm->state == Z_NULL )
	{
		return complen + 6;
	}

	/* compute wrapper length */
	s = strm->state;
	switch( s->wrap )
	{
		case 0:                                 /* raw deflate */
			wraplen = 0;
			break;
		case 1:                                 /* zlib wrapper */
			wraplen = 6 + ( s->strstart ? 4 : 0 );
			break;
		case 2:                                 /* gzip wrapper */
			wraplen = 18;
			if( s->gzhead != Z_NULL )           /* user-supplied gzip header */
			{
				if( s->gzhead->extra != Z_NULL )
				{
					wraplen += 2 + s->gzhead->extra_len;
				}
				str = s->gzhead->name;
				if( str != Z_NULL )
					do
					{
						wraplen++;
					}
					while( *str++ );
				str = s->gzhead->comment;
				if( str != Z_NULL )
					do
					{
						wraplen++;
					}
					while( *str++ );
				if( s->gzhead->hcrc )
				{
					wraplen += 2;
				}
			}
			break;
		default:                                /* for compiler happiness */
			wraplen = 6;
	}

	/* if not default parameters, return conservative bound */
	if( s->w_bits != 15 || s->hash_bits != 8 + 7 )
	{
		return complen + wraplen;
	}

	/* default settings: return tight bound for that case */
	return sourceLen + ( sourceLen >> 12 ) + ( sourceLen >> 14 ) +
		   ( sourceLen >> 25 ) + 13 - 6 + wraplen;
}

/* =========================================================================
 * Put a short in the pending buffer. The 16-bit value is put in MSB order.
 * IN assertion: the stream state is correct and there is enough room in
 * pending_buf.
 */
local void putShortMSB( s, b )
deflate_state* s;
uInt b;
{
	put_byte( s, ( Byte )( b >> 8 ) );
	put_byte( s, ( Byte )( b & 0xff ) );
}

/* =========================================================================
 * Flush as much pending output as possible. All deflate() output goes
 * through this function so some applications may wish to modify it
 * to avoid allocating a large strm->next_out buffer and copying into it.
 * (See also read_buf()).
 */
local void flush_pending( strm )
z_streamp strm;
{
	unsigned len;
	deflate_state* s = strm->state;

	_tr_flush_bits( s );
	len = s->pending;
	if( len > strm->avail_out )
	{
		len = strm->avail_out;
	}
	if( len == 0 )
	{
		return;
	}

	zmemcpy( strm->next_out, s->pending_out, len );
	strm->next_out  += len;
	s->pending_out  += len;
	strm->total_out += len;
	strm->avail_out  -= len;
	s->pending -= len;
	if( s->pending == 0 )
	{
		s->pending_out = s->pending_buf;
	}
}

/* ========================================================================= */
int ZEXPORT deflate( strm, flush )
z_streamp strm;
int flush;
{
	int old_flush; /* value of flush param for previous deflate call */
	deflate_state* s;

	if( strm == Z_NULL || strm->state == Z_NULL ||
			flush > Z_BLOCK || flush < 0 )
	{
		return Z_STREAM_ERROR;
	}
	s = strm->state;

	if( strm->next_out == Z_NULL ||
			( strm->next_in == Z_NULL && strm->avail_in != 0 ) ||
			( s->status == FINISH_STATE && flush != Z_FINISH ) )
	{
		ERR_RETURN( strm, Z_STREAM_ERROR );
	}
	if( strm->avail_out == 0 )
	{
		ERR_RETURN( strm, Z_BUF_ERROR );
	}

	s->strm = strm; /* just in case */
	old_flush = s->last_flush;
	s->last_flush = flush;

	/* Write the header */
	if( s->status == INIT_STATE )
	{
#ifdef GZIP
		if( s->wrap == 2 )
		{
			strm->adler = crc32( 0L, Z_NULL, 0 );
			put_byte( s, 31 );
			put_byte( s, 139 );
			put_byte( s, 8 );
			if( s->gzhead == Z_NULL )
			{
				put_byte( s, 0 );
				put_byte( s, 0 );
				put_byte( s, 0 );
				put_byte( s, 0 );
				put_byte( s, 0 );
				put_byte( s, s->level == 9 ? 2 :
						  ( s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
							4 : 0 ) );
				put_byte( s, OS_CODE );
				s->status = BUSY_STATE;
			}
			else
			{
				put_byte( s, ( s->gzhead->text ? 1 : 0 ) +
						  ( s->gzhead->hcrc ? 2 : 0 ) +
						  ( s->gzhead->extra == Z_NULL ? 0 : 4 ) +
						  ( s->gzhead->name == Z_NULL ? 0 : 8 ) +
						  ( s->gzhead->comment == Z_NULL ? 0 : 16 )
						);
				put_byte( s, ( Byte )( s->gzhead->time & 0xff ) );
				put_byte( s, ( Byte )( ( s->gzhead->time >> 8 ) & 0xff ) );
				put_byte( s, ( Byte )( ( s->gzhead->time >> 16 ) & 0xff ) );
				put_byte( s, ( Byte )( ( s->gzhead->time >> 24 ) & 0xff ) );
				put_byte( s, s->level == 9 ? 2 :
						  ( s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
							4 : 0 ) );
				put_byte( s, s->gzhead->os & 0xff );
				if( s->gzhead->extra != Z_NULL )
				{
					put_byte( s, s->gzhead->extra_len & 0xff );
					put_byte( s, ( s->gzhead->extra_len >> 8 ) & 0xff );
				}
				if( s->gzhead->hcrc )
					strm->adler = crc32( strm->adler, s->pending_buf,
										 s->pending );
				s->gzindex = 0;
				s->status = EXTRA_STATE;
			}
		}
		else
#endif
		{
			uInt header = ( Z_DEFLATED + ( ( s->w_bits - 8 ) << 4 ) ) << 8;
			uInt level_flags;

			if( s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 )
			{
				level_flags = 0;
			}
			else if( s->level < 6 )
			{
				level_flags = 1;
			}
			else if( s->level == 6 )
			{
				level_flags = 2;
			}
			else
			{
				level_flags = 3;
			}
			header |= ( level_flags << 6 );
			if( s->strstart != 0 )
			{
				header |= PRESET_DICT;
			}
			header += 31 - ( header % 31 );

			s->status = BUSY_STATE;
			putShortMSB( s, header );

			/* Save the adler32 of the preset dictionary: */
			if( s->strstart != 0 )
			{
				putShortMSB( s, ( uInt )( strm->adler >> 16 ) );
				putShortMSB( s, ( uInt )( strm->adler & 0xffff ) );
			}
			strm->adler = adler32( 0L, Z_NULL, 0 );
		}
	}
#ifdef GZIP
	if( s->status == EXTRA_STATE )
	{
		if( s->gzhead->extra != Z_NULL )
		{
			uInt beg = s->pending;  /* start of bytes to update crc */

			while( s->gzindex < ( s->gzhead->extra_len & 0xffff ) )
			{
				if( s->pending == s->pending_buf_size )
				{
					if( s->gzhead->hcrc && s->pending > beg )
						strm->adler = crc32( strm->adler, s->pending_buf + beg,
											 s->pending - beg );
					flush_pending( strm );
					beg = s->pending;
					if( s->pending == s->pending_buf_size )
					{
						break;
					}
				}
				put_byte( s, s->gzhead->extra[s->gzindex] );
				s->gzindex++;
			}
			if( s->gzhead->hcrc && s->pending > beg )
				strm->adler = crc32( strm->adler, s->pending_buf + beg,
									 s->pending - beg );
			if( s->gzindex == s->gzhead->extra_len )
			{
				s->gzindex = 0;
				s->status = NAME_STATE;
			}
		}
		else
		{
			s->status = NAME_STATE;
		}
	}
	if( s->status == NAME_STATE )
	{
		if( s->gzhead->name != Z_NULL )
		{
			uInt beg = s->pending;  /* start of bytes to update crc */
			int val;

			do
			{
				if( s->pending == s->pending_buf_size )
				{
					if( s->gzhead->hcrc && s->pending > beg )
						strm->adler = crc32( strm->adler, s->pending_buf + beg,
											 s->pending - beg );
					flush_pending( strm );
					beg = s->pending;
					if( s->pending == s->pending_buf_size )
					{
						val = 1;
						break;
					}
				}
				val = s->gzhead->name[s->gzindex++];
				put_byte( s, val );
			}
			while( val != 0 );
			if( s->gzhead->hcrc && s->pending > beg )
				strm->adler = crc32( strm->adler, s->pending_buf + beg,
									 s->pending - beg );
			if( val == 0 )
			{
				s->gzindex = 0;
				s->status = COMMENT_STATE;
			}
		}
		else
		{
			s->status = COMMENT_STATE;
		}
	}
	if( s->status == COMMENT_STATE )
	{
		if( s->gzhead->comment != Z_NULL )
		{
			uInt beg = s->pending;  /* start of bytes to update crc */
			int val;

			do
			{
				if( s->pending == s->pending_buf_size )
				{
					if( s->gzhead->hcrc && s->pending > beg )
						strm->adler = crc32( strm->adler, s->pending_buf + beg,
											 s->pending - beg );
					flush_pending( strm );
					beg = s->pending;
					if( s->pending == s->pending_buf_size )
					{
						val = 1;
						break;
					}
				}
				val = s->gzhead->comment[s->gzindex++];
				put_byte( s, val );
			}
			while( val != 0 );
			if( s->gzhead->hcrc && s->pending > beg )
				strm->adler = crc32( strm->adler, s->pending_buf + beg,
									 s->pending - beg );
			if( val == 0 )
			{
				s->status = HCRC_STATE;
			}
		}
		else
		{
			s->status = HCRC_STATE;
		}
	}
	if( s->status == HCRC_STATE )
	{
		if( s->gzhead->hcrc )
		{
			if( s->pending + 2 > s->pending_buf_size )
			{
				flush_pending( strm );
			}
			if( s->pending + 2 <= s->pending_buf_size )
			{
				put_byte( s, ( Byte )( strm->adler & 0xff ) );
				put_byte( s, ( Byte )( ( strm->adler >> 8 ) & 0xff ) );
				strm->adler = crc32( 0L, Z_NULL, 0 );
				s->status = BUSY_STATE;
			}
		}
		else
		{
			s->status = BUSY_STATE;
		}
	}
#endif

	/* Flush as much pending output as possible */
	if( s->pending != 0 )
	{
		flush_pending( strm );
		if( strm->avail_out == 0 )
		{
			/* Since avail_out is 0, deflate will be called again with
			 * more output space, but possibly with both pending and
			 * avail_in equal to zero. There won't be anything to do,
			 * but this is not an error situation so make sure we
			 * return OK instead of BUF_ERROR at next call of deflate:
			 */
			s->last_flush = -1;
			return Z_OK;
		}

		/* Make sure there is something to do and avoid duplicate consecutive
		 * flushes. For repeated and useless calls with Z_FINISH, we keep
		 * returning Z_STREAM_END instead of Z_BUF_ERROR.
		 */
	}
	else if( strm->avail_in == 0 && RANK( flush ) <= RANK( old_flush ) &&
			 flush != Z_FINISH )
	{
		ERR_RETURN( strm, Z_BUF_ERROR );
	}

	/* User must not provide more input after the first FINISH: */
	if( s->status == FINISH_STATE && strm->avail_in != 0 )
	{
		ERR_RETURN( strm, Z_BUF_ERROR );
	}

	/* Start a new block or continue the current one.
	 */
	if( strm->avail_in != 0 || s->lookahead != 0 ||
			( flush != Z_NO_FLUSH && s->status != FINISH_STATE ) )
	{
		block_state bstate;

		bstate = s->strategy == Z_HUFFMAN_ONLY ? deflate_huff( s, flush ) :
				 ( s->strategy == Z_RLE ? deflate_rle( s, flush ) :
				   ( *( configuration_table[s->level].func ) )( s, flush ) );

		if( bstate == finish_started || bstate == finish_done )
		{
			s->status = FINISH_STATE;
		}
		if( bstate == need_more || bstate == finish_started )
		{
			if( strm->avail_out == 0 )
			{
				s->last_flush = -1; /* avoid BUF_ERROR next call, see above */
			}
			return Z_OK;
			/* If flush != Z_NO_FLUSH && avail_out == 0, the next call
			 * of deflate should use the same flush parameter to make sure
			 * that the flush is complete. So we don't have to output an
			 * empty block here, this will be done at next call. This also
			 * ensures that for a very small output buffer, we emit at most
			 * one empty block.
			 */
		}
		if( bstate == block_done )
		{
			if( flush == Z_PARTIAL_FLUSH )
			{
				_tr_align( s );
			}
			else if( flush != Z_BLOCK )    /* FULL_FLUSH or SYNC_FLUSH */
			{
				_tr_stored_block( s, ( char* )0, 0L, 0 );
				/* For a full flush, this empty block will be recognized
				 * as a special marker by inflate_sync().
				 */
				if( flush == Z_FULL_FLUSH )
				{
					CLEAR_HASH( s );           /* forget history */
					if( s->lookahead == 0 )
					{
						s->strstart = 0;
						s->block_start = 0L;
						s->insert = 0;
					}
				}
			}
			flush_pending( strm );
			if( strm->avail_out == 0 )
			{
				s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */
				return Z_OK;
			}
		}
	}
	Assert( strm->avail_out > 0, "bug2" );

	if( flush != Z_FINISH )
	{
		return Z_OK;
	}
	if( s->wrap <= 0 )
	{
		return Z_STREAM_END;
	}

	/* Write the trailer */
#ifdef GZIP
	if( s->wrap == 2 )
	{
		put_byte( s, ( Byte )( strm->adler & 0xff ) );
		put_byte( s, ( Byte )( ( strm->adler >> 8 ) & 0xff ) );
		put_byte( s, ( Byte )( ( strm->adler >> 16 ) & 0xff ) );
		put_byte( s, ( Byte )( ( strm->adler >> 24 ) & 0xff ) );
		put_byte( s, ( Byte )( strm->total_in & 0xff ) );
		put_byte( s, ( Byte )( ( strm->total_in >> 8 ) & 0xff ) );
		put_byte( s, ( Byte )( ( strm->total_in >> 16 ) & 0xff ) );
		put_byte( s, ( Byte )( ( strm->total_in >> 24 ) & 0xff ) );
	}
	else
#endif
	{
		putShortMSB( s, ( uInt )( strm->adler >> 16 ) );
		putShortMSB( s, ( uInt )( strm->adler & 0xffff ) );
	}
	flush_pending( strm );
	/* If avail_out is zero, the application will call deflate again
	 * to flush the rest.
	 */
	if( s->wrap > 0 )
	{
		s->wrap = -s->wrap;    /* write the trailer only once! */
	}
	return s->pending != 0 ? Z_OK : Z_STREAM_END;
}

/* ========================================================================= */
int ZEXPORT deflateEnd( strm )
z_streamp strm;
{
	int status;

	if( strm == Z_NULL || strm->state == Z_NULL )
	{
		return Z_STREAM_ERROR;
	}

	status = strm->state->status;
	if( status != INIT_STATE &&
			status != EXTRA_STATE &&
			status != NAME_STATE &&
			status != COMMENT_STATE &&
			status != HCRC_STATE &&
			status != BUSY_STATE &&
			status != FINISH_STATE )
	{
		return Z_STREAM_ERROR;
	}

	/* Deallocate in reverse order of allocations: */
	TRY_FREE( strm, strm->state->pending_buf );
	TRY_FREE( strm, strm->state->head );
	TRY_FREE( strm, strm->state->prev );
	TRY_FREE( strm, strm->state->window );

	ZFREE( strm, strm->state );
	strm->state = Z_NULL;

	return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK;
}

/* =========================================================================
 * Copy the source state to the destination state.
 * To simplify the source, this is not supported for 16-bit MSDOS (which
 * doesn't have enough memory anyway to duplicate compression states).
 */
int ZEXPORT deflateCopy( dest, source )
z_streamp dest;
z_streamp source;
{
#ifdef MAXSEG_64K
	return Z_STREAM_ERROR;
#else
	deflate_state* ds;
	deflate_state* ss;
	ushf* overlay;


	if( source == Z_NULL || dest == Z_NULL || source->state == Z_NULL )
	{
		return Z_STREAM_ERROR;
	}

	ss = source->state;

	zmemcpy( ( voidpf )dest, ( voidpf )source, sizeof( z_stream ) );

	ds = ( deflate_state* ) ZALLOC( dest, 1, sizeof( deflate_state ) );
	if( ds == Z_NULL )
	{
		return Z_MEM_ERROR;
	}
	dest->state = ( struct internal_state FAR* ) ds;
	zmemcpy( ( voidpf )ds, ( voidpf )ss, sizeof( deflate_state ) );
	ds->strm = dest;

	ds->window = ( Bytef* ) ZALLOC( dest, ds->w_size, 2 * sizeof( Byte ) );
	ds->prev   = ( Posf* )  ZALLOC( dest, ds->w_size, sizeof( Pos ) );
	ds->head   = ( Posf* )  ZALLOC( dest, ds->hash_size, sizeof( Pos ) );
	overlay = ( ushf* ) ZALLOC( dest, ds->lit_bufsize, sizeof( ush ) + 2 );
	ds->pending_buf = ( uchf* ) overlay;

	if( ds->window == Z_NULL || ds->prev == Z_NULL || ds->head == Z_NULL ||
			ds->pending_buf == Z_NULL )
	{
		deflateEnd( dest );
		return Z_MEM_ERROR;
	}
	/* following zmemcpy do not work for 16-bit MSDOS */
	zmemcpy( ds->window, ss->window, ds->w_size * 2 * sizeof( Byte ) );
	zmemcpy( ( voidpf )ds->prev, ( voidpf )ss->prev, ds->w_size * sizeof( Pos ) );
	zmemcpy( ( voidpf )ds->head, ( voidpf )ss->head, ds->hash_size * sizeof( Pos ) );
	zmemcpy( ds->pending_buf, ss->pending_buf, ( uInt )ds->pending_buf_size );

	ds->pending_out = ds->pending_buf + ( ss->pending_out - ss->pending_buf );
	ds->d_buf = overlay + ds->lit_bufsize / sizeof( ush );
	ds->l_buf = ds->pending_buf + ( 1 + sizeof( ush ) ) * ds->lit_bufsize;

	ds->l_desc.dyn_tree = ds->dyn_ltree;
	ds->d_desc.dyn_tree = ds->dyn_dtree;
	ds->bl_desc.dyn_tree = ds->bl_tree;

	return Z_OK;
#endif /* MAXSEG_64K */
}

/* ===========================================================================
 * Read a new buffer from the current input stream, update the adler32
 * and total number of bytes read.  All deflate() input goes through
 * this function so some applications may wish to modify it to avoid
 * allocating a large strm->next_in buffer and copying from it.
 * (See also flush_pending()).
 */
local int read_buf( strm, buf, size )
z_streamp strm;
Bytef* buf;
unsigned size;
{
	unsigned len = strm->avail_in;

	if( len > size )
	{
		len = size;
	}
	if( len == 0 )
	{
		return 0;
	}

	strm->avail_in  -= len;

	zmemcpy( buf, strm->next_in, len );
	if( strm->state->wrap == 1 )
	{
		strm->adler = adler32( strm->adler, buf, len );
	}
#ifdef GZIP
	else if( strm->state->wrap == 2 )
	{
		strm->adler = crc32( strm->adler, buf, len );
	}
#endif
	strm->next_in  += len;
	strm->total_in += len;

	return ( int )len;
}

/* ===========================================================================
 * Initialize the "longest match" routines for a new zlib stream
 */
local void lm_init( s )
deflate_state* s;
{
	s->window_size = ( ulg )2L * s->w_size;

	CLEAR_HASH( s );

	/* Set the default configuration parameters:
	 */
	s->max_lazy_match   = configuration_table[s->level].max_lazy;
	s->good_match       = configuration_table[s->level].good_length;
	s->nice_match       = configuration_table[s->level].nice_length;
	s->max_chain_length = configuration_table[s->level].max_chain;

	s->strstart = 0;
	s->block_start = 0L;
	s->lookahead = 0;
	s->insert = 0;
	s->match_length = s->prev_length = MIN_MATCH - 1;
	s->match_available = 0;
	s->ins_h = 0;
#ifndef FASTEST
#ifdef ASMV
	match_init(); /* initialize the asm code */
#endif
#endif
}

#ifndef FASTEST
/* ===========================================================================
 * Set match_start to the longest match starting at the given string and
 * return its length. Matches shorter or equal to prev_length are discarded,
 * in which case the result is equal to prev_length and match_start is
 * garbage.
 * IN assertions: cur_match is the head of the hash chain for the current
 *   string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1
 * OUT assertion: the match length is not greater than s->lookahead.
 */
#ifndef ASMV
/* For 80x86 and 680x0, an optimized version will be provided in match.asm or
 * match.S. The code will be functionally equivalent.
 */
local uInt longest_match( s, cur_match )
deflate_state* s;
IPos cur_match;                             /* current match */
{
	unsigned chain_length = s->max_chain_length;/* max hash chain length */
	register Bytef* scan = s->window + s->strstart; /* current string */
	register Bytef* match;                       /* matched string */
	register int len;                           /* length of current match */
	int best_len = s->prev_length;              /* best match length so far */
	int nice_match = s->nice_match;             /* stop if match long enough */
	IPos limit = s->strstart > ( IPos )MAX_DIST( s ) ?
				 s->strstart - ( IPos )MAX_DIST( s ) : NIL;
	/* Stop when cur_match becomes <= limit. To simplify the code,
	 * we prevent matches with the string of window index 0.
	 */
	Posf* prev = s->prev;
	uInt wmask = s->w_mask;

#ifdef UNALIGNED_OK
	/* Compare two bytes at a time. Note: this is not always beneficial.
	 * Try with and without -DUNALIGNED_OK to check.
	 */
	register Bytef* strend = s->window + s->strstart + MAX_MATCH - 1;
	register ush scan_start = *( ushf* )scan;
	register ush scan_end   = *( ushf* )( scan + best_len - 1 );
#else
	register Bytef* strend = s->window + s->strstart + MAX_MATCH;
	register Byte scan_end1  = scan[best_len - 1];
	register Byte scan_end   = scan[best_len];
#endif

	/* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
	 * It is easy to get rid of this optimization if necessary.
	 */
	Assert( s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever" );

	/* Do not waste too much time if we already have a good match: */
	if( s->prev_length >= s->good_match )
	{
		chain_length >>= 2;
	}
	/* Do not look for matches beyond the end of the input. This is necessary
	 * to make deflate deterministic.
	 */
	if( ( uInt )nice_match > s->lookahead )
	{
		nice_match = s->lookahead;
	}

	Assert( ( ulg )s->strstart <= s->window_size - MIN_LOOKAHEAD, "need lookahead" );

	do
	{
		Assert( cur_match < s->strstart, "no future" );
		match = s->window + cur_match;

		/* Skip to next match if the match length cannot increase
		 * or if the match length is less than 2.  Note that the checks below
		 * for insufficient lookahead only occur occasionally for performance
		 * reasons.  Therefore uninitialized memory will be accessed, and
		 * conditional jumps will be made that depend on those values.
		 * However the length of the match is limited to the lookahead, so
		 * the output of deflate is not affected by the uninitialized values.
		 */
#if (defined(UNALIGNED_OK) && MAX_MATCH == 258)
		/* This code assumes sizeof(unsigned short) == 2. Do not use
		 * UNALIGNED_OK if your compiler uses a different size.
		 */
		if( *( ushf* )( match + best_len - 1 ) != scan_end ||
				*( ushf* )match != scan_start )
		{
			continue;
		}

		/* It is not necessary to compare scan[2] and match[2] since they are
		 * always equal when the other bytes match, given that the hash keys
		 * are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at
		 * strstart+3, +5, ... up to strstart+257. We check for insufficient
		 * lookahead only every 4th comparison; the 128th check will be made
		 * at strstart+257. If MAX_MATCH-2 is not a multiple of 8, it is
		 * necessary to put more guard bytes at the end of the window, or
		 * to check more often for insufficient lookahead.
		 */
		Assert( scan[2] == match[2], "scan[2]?" );
		scan++, match++;
		do
		{
		}
		while( *( ushf* )( scan += 2 ) == *( ushf* )( match += 2 ) &&
				*( ushf* )( scan += 2 ) == *( ushf* )( match += 2 ) &&
				*( ushf* )( scan += 2 ) == *( ushf* )( match += 2 ) &&
				*( ushf* )( scan += 2 ) == *( ushf* )( match += 2 ) &&
				scan < strend );
		/* The funny "do {}" generates better code on most compilers */

		/* Here, scan <= window+strstart+257 */
		Assert( scan <= s->window + ( unsigned )( s->window_size - 1 ), "wild scan" );
		if( *scan == *match )
		{
			scan++;
		}

		len = ( MAX_MATCH - 1 ) - ( int )( strend - scan );
		scan = strend - ( MAX_MATCH - 1 );

#else /* UNALIGNED_OK */

		if( match[best_len]   != scan_end  ||
				match[best_len - 1] != scan_end1 ||
				*match            != *scan     ||
				*++match          != scan[1] )
		{
			continue;
		}

		/* The check at best_len-1 can be removed because it will be made
		 * again later. (This heuristic is not always a win.)
		 * It is not necessary to compare scan[2] and match[2] since they
		 * are always equal when the other bytes match, given that
		 * the hash keys are equal and that HASH_BITS >= 8.
		 */
		scan += 2, match++;
		Assert( *scan == *match, "match[2]?" );

		/* We check for insufficient lookahead only every 8th comparison;
		 * the 256th check will be made at strstart+258.
		 */
		do
		{
		}
		while( *++scan == *++match && *++scan == *++match &&
				*++scan == *++match && *++scan == *++match &&
				*++scan == *++match && *++scan == *++match &&
				*++scan == *++match && *++scan == *++match &&
				scan < strend );

		Assert( scan <= s->window + ( unsigned )( s->window_size - 1 ), "wild scan" );

		len = MAX_MATCH - ( int )( strend - scan );
		scan = strend - MAX_MATCH;

#endif /* UNALIGNED_OK */

		if( len > best_len )
		{
			s->match_start = cur_match;
			best_len = len;
			if( len >= nice_match )
			{
				break;
			}
#ifdef UNALIGNED_OK
			scan_end = *( ushf* )( scan + best_len - 1 );
#else
			scan_end1  = scan[best_len - 1];
			scan_end   = scan[best_len];
#endif
		}
	}
	while( ( cur_match = prev[cur_match & wmask] ) > limit
			&& --chain_length != 0 );

	if( ( uInt )best_len <= s->lookahead )
	{
		return ( uInt )best_len;
	}
	return s->lookahead;
}
#endif /* ASMV */

#else /* FASTEST */

/* ---------------------------------------------------------------------------
 * Optimized version for FASTEST only
 */
local uInt longest_match( s, cur_match )
deflate_state* s;
IPos cur_match;                             /* current match */
{
	register Bytef* scan = s->window + s->strstart; /* current string */
	register Bytef* match;                       /* matched string */
	register int len;                           /* length of current match */
	register Bytef* strend = s->window + s->strstart + MAX_MATCH;

	/* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
	 * It is easy to get rid of this optimization if necessary.
	 */
	Assert( s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever" );

	Assert( ( ulg )s->strstart <= s->window_size - MIN_LOOKAHEAD, "need lookahead" );

	Assert( cur_match < s->strstart, "no future" );

	match = s->window + cur_match;

	/* Return failure if the match length is less than 2:
	 */
	if( match[0] != scan[0] || match[1] != scan[1] )
	{
		return MIN_MATCH - 1;
	}

	/* The check at best_len-1 can be removed because it will be made
	 * again later. (This heuristic is not always a win.)
	 * It is not necessary to compare scan[2] and match[2] since they
	 * are always equal when the other bytes match, given that
	 * the hash keys are equal and that HASH_BITS >= 8.
	 */
	scan += 2, match += 2;
	Assert( *scan == *match, "match[2]?" );

	/* We check for insufficient lookahead only every 8th comparison;
	 * the 256th check will be made at strstart+258.
	 */
	do
	{
	}
	while( *++scan == *++match && *++scan == *++match &&
			*++scan == *++match && *++scan == *++match &&
			*++scan == *++match && *++scan == *++match &&
			*++scan == *++match && *++scan == *++match &&
			scan < strend );

	Assert( scan <= s->window + ( unsigned )( s->window_size - 1 ), "wild scan" );

	len = MAX_MATCH - ( int )( strend - scan );

	if( len < MIN_MATCH )
	{
		return MIN_MATCH - 1;
	}

	s->match_start = cur_match;
	return ( uInt )len <= s->lookahead ? ( uInt )len : s->lookahead;
}

#endif /* FASTEST */

#ifdef DEBUG
/* ===========================================================================
 * Check that the match at match_start is indeed a match.
 */
local void check_match( s, start, match, length )
deflate_state* s;
IPos start, match;
int length;
{
	/* check that the match is indeed a match */
	if( zmemcmp( s->window + match,
				 s->window + start, length ) != EQUAL )
	{
		fprintf( stderr, " start %u, match %u, length %d\n",
				 start, match, length );
		do
		{
			fprintf( stderr, "%c%c", s->window[match++], s->window[start++] );
		}
		while( --length != 0 );
		z_error( "invalid match" );
	}
	if( z_verbose > 1 )
	{
		fprintf( stderr, "\\[%d,%d]", start - match, length );
		do
		{
			putc( s->window[start++], stderr );
		}
		while( --length != 0 );
	}
}
#else
#  define check_match(s, start, match, length)
#endif /* DEBUG */

/* ===========================================================================
 * Fill the window when the lookahead becomes insufficient.
 * Updates strstart and lookahead.
 *
 * IN assertion: lookahead < MIN_LOOKAHEAD
 * OUT assertions: strstart <= window_size-MIN_LOOKAHEAD
 *    At least one byte has been read, or avail_in == 0; reads are
 *    performed for at least two bytes (required for the zip translate_eol
 *    option -- not supported here).
 */
local void fill_window( s )
deflate_state* s;
{
	register unsigned n, m;
	register Posf* p;
	unsigned more;    /* Amount of free space at the end of the window. */
	uInt wsize = s->w_size;

	Assert( s->lookahead < MIN_LOOKAHEAD, "already enough lookahead" );

	do
	{
		more = ( unsigned )( s->window_size - ( ulg )s->lookahead - ( ulg )s->strstart );

		/* Deal with !@#$% 64K limit: */
		if( sizeof( int ) <= 2 )
		{
			if( more == 0 && s->strstart == 0 && s->lookahead == 0 )
			{
				more = wsize;

			}
			else if( more == ( unsigned )( -1 ) )
			{
				/* Very unlikely, but possible on 16 bit machine if
				 * strstart == 0 && lookahead == 1 (input done a byte at time)
				 */
				more--;
			}
		}

		/* If the window is almost full and there is insufficient lookahead,
		 * move the upper half to the lower one to make room in the upper half.
		 */
		if( s->strstart >= wsize + MAX_DIST( s ) )
		{

			zmemcpy( s->window, s->window + wsize, ( unsigned )wsize );
			s->match_start -= wsize;
			s->strstart    -= wsize; /* we now have strstart >= MAX_DIST */
			s->block_start -= ( long ) wsize;

			/* Slide the hash table (could be avoided with 32 bit values
			   at the expense of memory usage). We slide even when level == 0
			   to keep the hash table consistent if we switch back to level > 0
			   later. (Using level 0 permanently is not an optimal usage of
			   zlib, so we don't care about this pathological case.)
			 */
			n = s->hash_size;
			p = &s->head[n];
			do
			{
				m = *--p;
				*p = ( Pos )( m >= wsize ? m - wsize : NIL );
			}
			while( --n );

			n = wsize;
#ifndef FASTEST
			p = &s->prev[n];
			do
			{
				m = *--p;
				*p = ( Pos )( m >= wsize ? m - wsize : NIL );
				/* If n is not on any hash chain, prev[n] is garbage but
				 * its value will never be used.
				 */
			}
			while( --n );
#endif
			more += wsize;
		}
		if( s->strm->avail_in == 0 )
		{
			break;
		}

		/* If there was no sliding:
		 *    strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 &&
		 *    more == window_size - lookahead - strstart
		 * => more >= window_size - (MIN_LOOKAHEAD-1 + WSIZE + MAX_DIST-1)
		 * => more >= window_size - 2*WSIZE + 2
		 * In the BIG_MEM or MMAP case (not yet supported),
		 *   window_size == input_size + MIN_LOOKAHEAD  &&
		 *   strstart + s->lookahead <= input_size => more >= MIN_LOOKAHEAD.
		 * Otherwise, window_size == 2*WSIZE so more >= 2.
		 * If there was sliding, more >= WSIZE. So in all cases, more >= 2.
		 */
		Assert( more >= 2, "more < 2" );

		n = read_buf( s->strm, s->window + s->strstart + s->lookahead, more );
		s->lookahead += n;

		/* Initialize the hash value now that we have some input: */
		if( s->lookahead + s->insert >= MIN_MATCH )
		{
			uInt str = s->strstart - s->insert;
			s->ins_h = s->window[str];
			UPDATE_HASH( s, s->ins_h, s->window[str + 1] );
#if MIN_MATCH != 3
			Call UPDATE_HASH() MIN_MATCH - 3 more times
#endif
			while( s->insert )
			{
				UPDATE_HASH( s, s->ins_h, s->window[str + MIN_MATCH - 1] );
#ifndef FASTEST
				s->prev[str & s->w_mask] = s->head[s->ins_h];
#endif
				s->head[s->ins_h] = ( Pos )str;
				str++;
				s->insert--;
				if( s->lookahead + s->insert < MIN_MATCH )
				{
					break;
				}
			}
		}
		/* If the whole input has less than MIN_MATCH bytes, ins_h is garbage,
		 * but this is not important since only literal bytes will be emitted.
		 */

	}
	while( s->lookahead < MIN_LOOKAHEAD && s->strm->avail_in != 0 );

	/* If the WIN_INIT bytes after the end of the current data have never been
	 * written, then zero those bytes in order to avoid memory check reports of
	 * the use of uninitialized (or uninitialised as Julian writes) bytes by
	 * the longest match routines.  Update the high water mark for the next
	 * time through here.  WIN_INIT is set to MAX_MATCH since the longest match
	 * routines allow scanning to strstart + MAX_MATCH, ignoring lookahead.
	 */
	if( s->high_water < s->window_size )
	{
		ulg curr = s->strstart + ( ulg )( s->lookahead );
		ulg init;

		if( s->high_water < curr )
		{
			/* Previous high water mark below current data -- zero WIN_INIT
			 * bytes or up to end of window, whichever is less.
			 */
			init = s->window_size - curr;
			if( init > WIN_INIT )
			{
				init = WIN_INIT;
			}
			zmemzero( s->window + curr, ( unsigned )init );
			s->high_water = curr + init;
		}
		else if( s->high_water < ( ulg )curr + WIN_INIT )
		{
			/* High water mark at or above current data, but below current data
			 * plus WIN_INIT -- zero out to current data plus WIN_INIT, or up
			 * to end of window, whichever is less.
			 */
			init = ( ulg )curr + WIN_INIT - s->high_water;
			if( init > s->window_size - s->high_water )
			{
				init = s->window_size - s->high_water;
			}
			zmemzero( s->window + s->high_water, ( unsigned )init );
			s->high_water += init;
		}
	}

	Assert( ( ulg )s->strstart <= s->window_size - MIN_LOOKAHEAD,
			"not enough room for search" );
}

/* ===========================================================================
 * Flush the current block, with given end-of-file flag.
 * IN assertion: strstart is set to the end of the current match.
 */
#define FLUSH_BLOCK_ONLY(s, last) { \
   _tr_flush_block(s, (s->block_start >= 0L ? \
                   (charf *)&s->window[(unsigned)s->block_start] : \
                   (charf *)Z_NULL), \
                (ulg)((long)s->strstart - s->block_start), \
                (last)); \
   s->block_start = s->strstart; \
   flush_pending(s->strm); \
   Tracev((stderr,"[FLUSH]")); \
}

/* Same but force premature exit if necessary. */
#define FLUSH_BLOCK(s, last) { \
   FLUSH_BLOCK_ONLY(s, last); \
   if (s->strm->avail_out == 0) return (last) ? finish_started : need_more; \
}

/* ===========================================================================
 * Copy without compression as much as possible from the input stream, return
 * the current block state.
 * This function does not insert new strings in the dictionary since
 * uncompressible data is probably not useful. This function is used
 * only for the level=0 compression option.
 * NOTE: this function should be optimized to avoid extra copying from
 * window to pending_buf.
 */
local block_state deflate_stored( s, flush )
deflate_state* s;
int flush;
{
	/* Stored blocks are limited to 0xffff bytes, pending_buf is limited
	 * to pending_buf_size, and each stored block has a 5 byte header:
	 */
	ulg max_block_size = 0xffff;
	ulg max_start;

	if( max_block_size > s->pending_buf_size - 5 )
	{
		max_block_size = s->pending_buf_size - 5;
	}

	/* Copy as much as possible from input to output: */
	for( ;; )
	{
		/* Fill the window as much as possible: */
		if( s->lookahead <= 1 )
		{

			Assert( s->strstart < s->w_size + MAX_DIST( s ) ||
					s->block_start >= ( long )s->w_size, "slide too late" );

			fill_window( s );
			if( s->lookahead == 0 && flush == Z_NO_FLUSH )
			{
				return need_more;
			}

			if( s->lookahead == 0 )
			{
				break;    /* flush the current block */
			}
		}
		Assert( s->block_start >= 0L, "block gone" );

		s->strstart += s->lookahead;
		s->lookahead = 0;

		/* Emit a stored block if pending_buf will be full: */
		max_start = s->block_start + max_block_size;
		if( s->strstart == 0 || ( ulg )s->strstart >= max_start )
		{
			/* strstart == 0 is possible when wraparound on 16-bit machine */
			s->lookahead = ( uInt )( s->strstart - max_start );
			s->strstart = ( uInt )max_start;
			FLUSH_BLOCK( s, 0 );
		}
		/* Flush if we may have to slide, otherwise block_start may become
		 * negative and the data will be gone:
		 */
		if( s->strstart - ( uInt )s->block_start >= MAX_DIST( s ) )
		{
			FLUSH_BLOCK( s, 0 );
		}
	}
	s->insert = 0;
	if( flush == Z_FINISH )
	{
		FLUSH_BLOCK( s, 1 );
		return finish_done;
	}
	if( ( long )s->strstart > s->block_start )
	{
		FLUSH_BLOCK( s, 0 );
	}
	return block_done;
}

/* ===========================================================================
 * Compress as much as possible from the input stream, return the current
 * block state.
 * This function does not perform lazy evaluation of matches and inserts
 * new strings in the dictionary only for unmatched strings or for short
 * matches. It is used only for the fast compression options.
 */
local block_state deflate_fast( s, flush )
deflate_state* s;
int flush;
{
	IPos hash_head;       /* head of the hash chain */
	int bflush;           /* set if current block must be flushed */

	for( ;; )
	{
		/* Make sure that we always have enough lookahead, except
		 * at the end of the input file. We need MAX_MATCH bytes
		 * for the next match, plus MIN_MATCH bytes to insert the
		 * string following the next match.
		 */
		if( s->lookahead < MIN_LOOKAHEAD )
		{
			fill_window( s );
			if( s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH )
			{
				return need_more;
			}
			if( s->lookahead == 0 )
			{
				break;    /* flush the current block */
			}
		}

		/* Insert the string window[strstart .. strstart+2] in the
		 * dictionary, and set hash_head to the head of the hash chain:
		 */
		hash_head = NIL;
		if( s->lookahead >= MIN_MATCH )
		{
			INSERT_STRING( s, s->strstart, hash_head );
		}

		/* Find the longest match, discarding those <= prev_length.
		 * At this point we have always match_length < MIN_MATCH
		 */
		if( hash_head != NIL && s->strstart - hash_head <= MAX_DIST( s ) )
		{
			/* To simplify the code, we prevent matches with the string
			 * of window index 0 (in particular we have to avoid a match
			 * of the string with itself at the start of the input file).
			 */
			s->match_length = longest_match( s, hash_head );
			/* longest_match() sets match_start */
		}
		if( s->match_length >= MIN_MATCH )
		{
			check_match( s, s->strstart, s->match_start, s->match_length );

			_tr_tally_dist( s, s->strstart - s->match_start,
							s->match_length - MIN_MATCH, bflush );

			s->lookahead -= s->match_length;

			/* Insert new strings in the hash table only if the match length
			 * is not too large. This saves time but degrades compression.
			 */
#ifndef FASTEST
			if( s->match_length <= s->max_insert_length &&
					s->lookahead >= MIN_MATCH )
			{
				s->match_length--; /* string at strstart already in table */
				do
				{
					s->strstart++;
					INSERT_STRING( s, s->strstart, hash_head );
					/* strstart never exceeds WSIZE-MAX_MATCH, so there are
					 * always MIN_MATCH bytes ahead.
					 */
				}
				while( --s->match_length != 0 );
				s->strstart++;
			}
			else
#endif
			{
				s->strstart += s->match_length;
				s->match_length = 0;
				s->ins_h = s->window[s->strstart];
				UPDATE_HASH( s, s->ins_h, s->window[s->strstart + 1] );
#if MIN_MATCH != 3
				Call UPDATE_HASH() MIN_MATCH - 3 more times
#endif
				/* If lookahead < MIN_MATCH, ins_h is garbage, but it does not
				 * matter since it will be recomputed at next deflate call.
				 */
			}
		}
		else
		{
			/* No match, output a literal byte */
			Tracevv( ( stderr, "%c", s->window[s->strstart] ) );
			_tr_tally_lit( s, s->window[s->strstart], bflush );
			s->lookahead--;
			s->strstart++;
		}
		if( bflush )
		{
			FLUSH_BLOCK( s, 0 );
		}
	}
	s->insert = s->strstart < MIN_MATCH - 1 ? s->strstart : MIN_MATCH - 1;
	if( flush == Z_FINISH )
	{
		FLUSH_BLOCK( s, 1 );
		return finish_done;
	}
	if( s->last_lit )
	{
		FLUSH_BLOCK( s, 0 );
	}
	return block_done;
}

#ifndef FASTEST
/* ===========================================================================
 * Same as above, but achieves better compression. We use a lazy
 * evaluation for matches: a match is finally adopted only if there is
 * no better match at the next window position.
 */
local block_state deflate_slow( s, flush )
deflate_state* s;
int flush;
{
	IPos hash_head;          /* head of hash chain */
	int bflush;              /* set if current block must be flushed */

	/* Process the input block. */
	for( ;; )
	{
		/* Make sure that we always have enough lookahead, except
		 * at the end of the input file. We need MAX_MATCH bytes
		 * for the next match, plus MIN_MATCH bytes to insert the
		 * string following the next match.
		 */
		if( s->lookahead < MIN_LOOKAHEAD )
		{
			fill_window( s );
			if( s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH )
			{
				return need_more;
			}
			if( s->lookahead == 0 )
			{
				break;    /* flush the current block */
			}
		}

		/* Insert the string window[strstart .. strstart+2] in the
		 * dictionary, and set hash_head to the head of the hash chain:
		 */
		hash_head = NIL;
		if( s->lookahead >= MIN_MATCH )
		{
			INSERT_STRING( s, s->strstart, hash_head );
		}

		/* Find the longest match, discarding those <= prev_length.
		 */
		s->prev_length = s->match_length, s->prev_match = s->match_start;
		s->match_length = MIN_MATCH - 1;

		if( hash_head != NIL && s->prev_length < s->max_lazy_match &&
				s->strstart - hash_head <= MAX_DIST( s ) )
		{
			/* To simplify the code, we prevent matches with the string
			 * of window index 0 (in particular we have to avoid a match
			 * of the string with itself at the start of the input file).
			 */
			s->match_length = longest_match( s, hash_head );
			/* longest_match() sets match_start */

			if( s->match_length <= 5 && ( s->strategy == Z_FILTERED
#if TOO_FAR <= 32767
										  || ( s->match_length == MIN_MATCH &&
											   s->strstart - s->match_start > TOO_FAR )
#endif
										) )
			{

				/* If prev_match is also MIN_MATCH, match_start is garbage
				 * but we will ignore the current match anyway.
				 */
				s->match_length = MIN_MATCH - 1;
			}
		}
		/* If there was a match at the previous step and the current
		 * match is not better, output the previous match:
		 */
		if( s->prev_length >= MIN_MATCH && s->match_length <= s->prev_length )
		{
			uInt max_insert = s->strstart + s->lookahead - MIN_MATCH;
			/* Do not insert strings in hash table beyond this. */

			check_match( s, s->strstart - 1, s->prev_match, s->prev_length );

			_tr_tally_dist( s, s->strstart - 1 - s->prev_match,
							s->prev_length - MIN_MATCH, bflush );

			/* Insert in hash table all strings up to the end of the match.
			 * strstart-1 and strstart are already inserted. If there is not
			 * enough lookahead, the last two strings are not inserted in
			 * the hash table.
			 */
			s->lookahead -= s->prev_length - 1;
			s->prev_length -= 2;
			do
			{
				if( ++s->strstart <= max_insert )
				{
					INSERT_STRING( s, s->strstart, hash_head );
				}
			}
			while( --s->prev_length != 0 );
			s->match_available = 0;
			s->match_length = MIN_MATCH - 1;
			s->strstart++;

			if( bflush )
			{
				FLUSH_BLOCK( s, 0 );
			}

		}
		else if( s->match_available )
		{
			/* If there was no match at the previous position, output a
			 * single literal. If there was a match but the current match
			 * is longer, truncate the previous match to a single literal.
			 */
			Tracevv( ( stderr, "%c", s->window[s->strstart - 1] ) );
			_tr_tally_lit( s, s->window[s->strstart - 1], bflush );
			if( bflush )
			{
				FLUSH_BLOCK_ONLY( s, 0 );
			}
			s->strstart++;
			s->lookahead--;
			if( s->strm->avail_out == 0 )
			{
				return need_more;
			}
		}
		else
		{
			/* There is no previous match to compare with, wait for
			 * the next step to decide.
			 */
			s->match_available = 1;
			s->strstart++;
			s->lookahead--;
		}
	}
	Assert( flush != Z_NO_FLUSH, "no flush?" );
	if( s->match_available )
	{
		Tracevv( ( stderr, "%c", s->window[s->strstart - 1] ) );
		_tr_tally_lit( s, s->window[s->strstart - 1], bflush );
		s->match_available = 0;
	}
	s->insert = s->strstart < MIN_MATCH - 1 ? s->strstart : MIN_MATCH - 1;
	if( flush == Z_FINISH )
	{
		FLUSH_BLOCK( s, 1 );
		return finish_done;
	}
	if( s->last_lit )
	{
		FLUSH_BLOCK( s, 0 );
	}
	return block_done;
}
#endif /* FASTEST */

/* ===========================================================================
 * For Z_RLE, simply look for runs of bytes, generate matches only of distance
 * one.  Do not maintain a hash table.  (It will be regenerated if this run of
 * deflate switches away from Z_RLE.)
 */
local block_state deflate_rle( s, flush )
deflate_state* s;
int flush;
{
	int bflush;             /* set if current block must be flushed */
	uInt prev;              /* byte at distance one to match */
	Bytef* scan, *strend;   /* scan goes up to strend for length of run */

	for( ;; )
	{
		/* Make sure that we always have enough lookahead, except
		 * at the end of the input file. We need MAX_MATCH bytes
		 * for the longest run, plus one for the unrolled loop.
		 */
		if( s->lookahead <= MAX_MATCH )
		{
			fill_window( s );
			if( s->lookahead <= MAX_MATCH && flush == Z_NO_FLUSH )
			{
				return need_more;
			}
			if( s->lookahead == 0 )
			{
				break;    /* flush the current block */
			}
		}

		/* See how many times the previous byte repeats */
		s->match_length = 0;
		if( s->lookahead >= MIN_MATCH && s->strstart > 0 )
		{
			scan = s->window + s->strstart - 1;
			prev = *scan;
			if( prev == *++scan && prev == *++scan && prev == *++scan )
			{
				strend = s->window + s->strstart + MAX_MATCH;
				do
				{
				}
				while( prev == *++scan && prev == *++scan &&
						prev == *++scan && prev == *++scan &&
						prev == *++scan && prev == *++scan &&
						prev == *++scan && prev == *++scan &&
						scan < strend );
				s->match_length = MAX_MATCH - ( int )( strend - scan );
				if( s->match_length > s->lookahead )
				{
					s->match_length = s->lookahead;
				}
			}
			Assert( scan <= s->window + ( uInt )( s->window_size - 1 ), "wild scan" );
		}

		/* Emit match if have run of MIN_MATCH or longer, else emit literal */
		if( s->match_length >= MIN_MATCH )
		{
			check_match( s, s->strstart, s->strstart - 1, s->match_length );

			_tr_tally_dist( s, 1, s->match_length - MIN_MATCH, bflush );

			s->lookahead -= s->match_length;
			s->strstart += s->match_length;
			s->match_length = 0;
		}
		else
		{
			/* No match, output a literal byte */
			Tracevv( ( stderr, "%c", s->window[s->strstart] ) );
			_tr_tally_lit( s, s->window[s->strstart], bflush );
			s->lookahead--;
			s->strstart++;
		}
		if( bflush )
		{
			FLUSH_BLOCK( s, 0 );
		}
	}
	s->insert = 0;
	if( flush == Z_FINISH )
	{
		FLUSH_BLOCK( s, 1 );
		return finish_done;
	}
	if( s->last_lit )
	{
		FLUSH_BLOCK( s, 0 );
	}
	return block_done;
}

/* ===========================================================================
 * For Z_HUFFMAN_ONLY, do not look for matches.  Do not maintain a hash table.
 * (It will be regenerated if this run of deflate switches away from Huffman.)
 */
local block_state deflate_huff( s, flush )
deflate_state* s;
int flush;
{
	int bflush;             /* set if current block must be flushed */

	for( ;; )
	{
		/* Make sure that we have a literal to write. */
		if( s->lookahead == 0 )
		{
			fill_window( s );
			if( s->lookahead == 0 )
			{
				if( flush == Z_NO_FLUSH )
				{
					return need_more;
				}
				break;      /* flush the current block */
			}
		}

		/* Output a literal byte */
		s->match_length = 0;
		Tracevv( ( stderr, "%c", s->window[s->strstart] ) );
		_tr_tally_lit( s, s->window[s->strstart], bflush );
		s->lookahead--;
		s->strstart++;
		if( bflush )
		{
			FLUSH_BLOCK( s, 0 );
		}
	}
	s->insert = 0;
	if( flush == Z_FINISH )
	{
		FLUSH_BLOCK( s, 1 );
		return finish_done;
	}
	if( s->last_lit )
	{
		FLUSH_BLOCK( s, 0 );
	}
	return block_done;
}
